In chemistry, dioxirane is a compound with formula , whose molecule consists of a ring with one

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

and two

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

atoms, and two

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

atoms attached to the carbon. It is a heterocyclic compound, the smallest cyclic organic

peroxide In chemistry, peroxides are a group of compounds with the structure , where R = any element. The group in a peroxide is called the peroxide group or peroxo group. The nomenclature is somewhat variable. The most common peroxide is hydrogen ...

. The compound itself is highly unstable and has never been observed at room temperature. Derivatives in which the hydrogens are replaced by other

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the re ...

s are called dioxiranes, and may be more stable. Some of them, such as

dimethyldioxirane Dimethyldioxirane (DMDO), also referred to as Murray's reagent in reference to Robert W. Murray, is a dioxirane derived from acetone and can be considered as a monomer of acetone peroxide. It is a powerful yet selective oxidizing agent which fi ...

(DMDO) and the more reactive methyl(trifluoromethyl)dioxirane, are used in organic synthesis as oxidizing reagents, most notably as the key catalytic intermediate in the

Shi epoxidation The Shi epoxidation is a chemical reaction described as the asymmetric epoxidation of alkenes with oxone (potassium peroxymonosulfate) and a fructose-derived catalyst (1). This reaction is thought to proceed via a dioxirane intermediate, generated ...

reaction. Difluorodioxirane, which boils at about –80 to –90 °C, is one of the very few dioxirane derivatives that is stable in pure form at room temperature.

Synthesis

Dioxirane is highly unstable and the majority of studies of it have been

computational Computation is any type of arithmetic or non-arithmetic calculation that follows a well-defined model (e.g., an algorithm). Mechanical or electronic devices (or, historically, people) that perform computations are known as ''computers''. An espe ...

; it has been detected during the low temperature (-196 °C) reaction of ethylene and

ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...

, although even at these temperatures such a mixture can be explosive. Its formation is thought to be radical in nature, preceding via a

Criegee intermediate A Criegee intermediate (also called a Criegee zwitterion or Criegee biradical) is a carbonyl oxide with two charge centres. These chemicals may react with sulfur dioxide and nitrogen oxides in the earth's atmosphere, and are implicated in the f ...

. Microwave analysis has indicated C-H, C-O and O-O

bond length In molecular geometry, bond length or bond distance is defined as the average distance between nuclei of two bonded atoms in a molecule. It is a transferable property of a bond between atoms of fixed types, relatively independent of the rest of ...

s of 1.090, 1.388 and 1.516 Å respectively. The very long and weak O-O bond (c.f.

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%� ...

O-O = 1.47 Å) is the origin of its instability.

References

{{Functional group Functional groups Organic peroxides

Synthesis

See also

References